Even with all the advances of nowadays portable Information and Communications Technology (ICT) devices, such as, smart phone, tablet computer, system crash due to sudden power cut-off when the battery capacity is low is not uncommon. The main reason for such power cut-off can be explained as follows: the “polarization loss” and associated “impedance” of a Li-ion battery will become very high when the State of Charge (SoC) runs low. The same power fluctuations/surges resulted from running different programs and functions in an ICT device will cause bigger voltage fluctuations at low battery SoC stage. Battery low voltage protection will be activated to cut off the power when a voltage fluctuation reaches the lower voltage threshold. Such low SoC voltage fluctuation will be even bigger for an aged battery due to its impedance increase, and also results in the reduction of precaution lead time for an ICT system to make properly data save and system turn-off. Most of existing power management methods are based on electric/electronics considerations, while battery characteristic curve (BCC) is based on the electrochemical characteristics of a battery shown in FIG. 1. BCC transforms the electrochemical characteristics to a popular electronics control domain (Potential-Capacity domain) which enables a quantitative and simple control algorithm. BCC is particularly useful in the low SoC state when the concentration polarization loss is high.
A known problem of the contemporary batteries for electronic devices in low capacity state is that a power surge may occur during the operation to cause the system to shutdown before using up the remaining power in the batteries in low capacity state. The current power management technique it to restrict the user from using functions that consumes a large amount of power in order to prolong the use time of the electronic device when the battery is low. However, the imposed restriction in the power manage technique may cause great inconvenience because the user often intends to use functions that consume more power, such as, making phone calls, sending e-mail with attachments, and so on. At the point of peak power consumption, a battery in low capacity state may reaches the threshold defined for the minimum safe voltage, which will force the battery protection circuit to cut off the battery circuit and shutdown the system without warning when no other effective management is adopted. The observation shows that the peak power consumption often occurs when a function is started for execution, and therefore, the starting of execution of an important function often leads to a premature power shutdown when the peak power consumption exceeds the safety threshold. As a result, the remaining battery capacity is not appropriately utilized even when the remaining power may be sufficient to keep the system operating some important functions for a little longer.